Fuel injectors in general have long been used for injecting fuel into an internal combustion engine. Such fuel injectors typically include an elongated body having an armature carrying a valve and a needle or pin which, under the bias of a spring, normally closes an orifice through a seat at one end of the injector. By periodically pulsing a coil within the injector body, the valve is periodically opened and closed to supply fuel through the orifice to the engine cylinder. Typically, the spray pattern flowing from the injector is in a swirling conical shape. It is quantitatively dominated by an outer conical wall of spray, with substantially smaller quantities of the fuel from the injector flowing interiorly within the conically-shaped spray. The axis of the conical spray pattern is generally directed to an optimal part of the engine or fuel injection system and the injector is normally oriented so that the injector axis and the conical spray pattern axis are coincident with one another.
In certain engines, however, constraints imposed on the mounting of the injectors have indicated a need for directing the conical spray to the optimum part of the engine or fuel injection system, while simultaneously mounting the injector at a location and in a position wherein the axis of the injector does not coincide with the axis of the conical spray pattern. Consequently, a problem arises as to how to simultaneously direct a swirling conical spray pattern to the optimal part of the engine or fuel injection system while enabling the injector to be mounted at an angle offset from the axis of the conical spray pattern.
One effort to direct a conical spray pattern having a swirl associated with the pattern is disclosed in an article appearing in SAE Publication 970540, titled "Development of Direct Injection Gasoline Engine." The injector disclosed in that article, has what appears to be a spray pattern inclined at an angle from the axis of the injector, an upstream swirler and a downstream orifice apparently angled off the longitudinal axis of the injector. However, an intermediate chamber or pocket lies between the swirler and the angled orifice of that injector and which chamber is enlarged relative to the orifice. The pocket, however, diminishes the swirl pattern to such an extent that when the fuel leaves the injector such fuel is not significantly swirling. That is, the swirl pattern effected by the swirler upstream of the valve seat is substantially diminished as the fuel leaves the valve seat and enters and exits the pocket. Because of the many angled surfaces defining the pocket, it detrimentally diminishes the effect of the swirl pattern imparted upstream of the pocket by the swirler to the extent that the conical spray emitted from the injector has very little, if any, swirl effect.